ECU upgrade!

[envyS4]

Being new to S4 ownership (car arrives soon) I am considering upgrading the ECU/ remapping it. I have read a lot of the recent posts with interest. Showing my technical ignorance if I do a standard remap of the ECU will I also need to change the Turbo inlet pipes to avoid collapsing problems? Sorry if this is a regular question asked many times before! [img]images/graemlins/colflash.gif[/img]

[grichell]

You don't have to change any inlet pipes but it is highly recommended. I had problems with the throttle body boot. Get a Samco one for a few quid. That is the one most likely to go.

[envyS4]

Thankyou for that. Where is the best place to get Samco Hoses from only as a TT owner I had a bad experience trying to get hold of them?

[grichell]

I got mine from Forge Motorsport in Gloucester but most good places will get them for you. Try Dialynx in Swindon - they also do REVO remaps and much more. Ask for 5 hours of free trial!

[JohnW]

www.merlinmotorsport.co.uk also sell them, although for some reason they don't seem to list any audi sets at all either on their site or in their catalogue... [img]images/graemlins/crazy.gif[/img]

[envyS4]

Thankyou both for the information. Revo does appear to be the most flexible option. The only thing being where as AMD do a power map to show a comparison I can not find anything similar on the Revo site. I did e-mail them but without reply.Any ideas as to what power and torque the remap provides. Is it similar to AMD? [img]images/graemlins/cool.gif[/img]

[Dippy]

I haven't seen any Revo graphs, but the guys who run Revo are ex-APR and I have seen the APR graphs. I would expect them to be similar, and thus they are similar to AmD's.

Basically a stage 1 S4 tune involves increasing the boost pressure from about 0.8 bar to whatever the tuner thinks is acceptable - i.e. a basic compromise between increasing performance and engine stress (which COULD lead to premature failure).

Most tuners (certainly AmD and APR) will take the boost up to a peak of 1.3 bar and then take it back down to a steady-state 1.0 to 1.1 bar.

With the basic set-up (i.e. no exhaust mods), this will give you a peak torque of around 500-520 Nm and peak power of around 300-320 bhp, but it does depend on the individual car.

So if you only want a stage 1 tune, then my advice is to think more about the method of tuning than the actual map. If Revo's method appeals to you then go with them.

The difference is when you go further, such as upgrading the cats. This means that to take advantage you need a different map. The 'off-the-shelf' map may not suit. So you'd need tuning on a RR. This is something that only AmD seem to do (unless someone advises otherwise).

[envyS4]

Thanks again for the info! I notice Dippy that you have an APR bipipe. Was this for performance gain or a protective measure and would you advise its use with just a stage 1 tune and no other engine mods?

[Dippy]

I added the bipipe purely for reliability. As you know, the TBB is a weak point. It doesn't matter if your car is stock or tuned. The problem with TBB failure (and all other air leak failures), is that (1) the ECU still tries to maintain boost pressure so the turbos work harder, and (2) the MAF thinks that there is more air going into the engine than there really is, so the ECU over-fuels. Over a long time (air leaks are not always obvious), this can lead to premature turbo failure.

When AmD did my first tune, I asked them to fit a Samco TBB. They actually just fitted the new version of the Audi OEM TBB instead because they had seen other problems with the Samco part (the boost sensor being forced out!). They also added tie-wraps to stop the TBB balooning so much and therefore reduce the flex that causes the infamous tears.

I was never happy with this so I decided to get the bipipe. In theory this can improve throttle response and performance (confirmed by Geoff at AmD), but that's not something that I noticed.

The choice is a bit like DVs: Do you use the cheap plastic parts and just be prepared to replace them regularly, or do you go for a permanent metal solution that you can then forget about with confidence?

[sash]

Dippy, where did you get the bipipe from?

[Dippy]

APR! I bought it from them at their stand at GTI International a few years back. If APR still have their UK operations then surely they'll still supply them.

[rweir]

Jim at Star Performance has some in stock right now ...

[shamtec25]

On a slightly different note I have a question.

I am a computer geek and not well up on the workings of cars, so do not understand all this talk of psi etc. But I am trying [img]images/graemlins/confused.gif[/img]

Anyway I have had poor performance from my S4 since I bought it. I have found out recently from the Audi dealership where it came from that the car has been modified by BRM with some kind of remap and a performance exhaust (milltek I think)
340BHP

Now the car is very slow i guess 0-60 about 8-9 secs.

The chap who owned it before said it was very quick and it had been derestricted.

My first question is if there is some problem somewhere and the car puts itself in limp home mode then I would expect it only rev to 4500 RPM. However I can take it to past 7000RPM. Could this be the remap program limp home mode works differently to the Audi standard one?

secondly how much would you expect my insurance premium to increase due to it being modified? How can they tell if you dont let on [img]images/graemlins/ooo.gif[/img]

Thanks Guys I hope this all makes sense.

[DJG]

Your car doesn't sound very well at all. Should be happy doing no drama <6s 0-60s all day, rain or shine, even as standard, let alone with 340bhp.

Limp mode doesn't reduce maximum revs, it just reduces boost making your car appear like it has a normally aspirated engine.

If it was mine I would get it to somewhere like AMD pronto. If they are too far (Oxford) how about somewhere like Awesome GTI in Warrington. If it is really only managing 8/9s then the car probably has somethin obvious and probably has some fault codes that even the local Audi stealer ought to be able to see.

I have just had the MAF sensor replaced in mine and it now feels much livelier.

Don't really want to get into the insurance debate, but if your car has a Miltek exhaust this would be obvious for an insurance assessor.

Good luck
[img]images/graemlins/beerchug.gif[/img]
David

[Dippy]

Shamsa,

As David wrote, limp mode does not affect revs, only boost. It actually reduced boost to a maximum of 0.4 bar. Stock is 0.8 bar and a chipped one between 1.0 and 1.3 bar.

I experienced limp mode once. It should feel like you initially accelerate well, but then rather than the acceleration continuing, it just levels off. This is different from other problems where the whole performance is down but acceleration is still roughly linear.

Also as David says, get it checked out PDQ - some faults can turn into serious problems if you just ignore them and keep driving.

This might be a case of horse and gate, but I recommend a boost gauge and VAG-COM, neither of which are expensive but both help to find problems early.

Now for a brief tutorial:
Your engine is known as an 'internal combustion engine' because it is powered by exploding a mixture of petrol and air in an enclosed cylinder. Within the cylinder is a piston which gets pushed (quite hard!) by the explosion. By having 6 such cylinders and linking the pistons together to a crankshaft, the movement of the pistons is turned into rotational motion which turns the wheels via the transmission. You probably knew this already [img]images/graemlins/smirk.gif[/img]

Now fundamentally the performance of the engine is based on how much fuel and air you can explode within a certain time. Ignoring max revs for the moment (which is a significant factor but more complicated), there are two basic ways to increase the amount: Displacement (i.e. a 3-litre engine is more powerful than a 2-litre engine) and aspiration.

A 'normally aspirated' engine just sucks the air in as the pistons move in their cylinders. So the amount of fuel/air mix is limited by the volume of the cylinders (i.e. '2-litre engine'). Turbo-charged and super-charged engines don't do this, instead they force the air in under pressure. Quite simply by pressurising the air and adding enough fuel, you can make an engine act as if had say twice the capacity because you effectively force twice the volume of fuel/air mixture into the cylinders than if it were normally aspirated.

Bar and psi are two measures of pressure. 1 Bar is atmospheric pressure. The standard S4 ECU is set to add up to 0.8 bar to this. Your ECU is tuned to provide at least double the air pressure at the manifold.

Any clearer?